1. Field of the Invention
The present invention relates to a display device, more particularly, relates to an active matrix organic light-emitting diode array substrate, a manufacturing method thereof and a display device including the same.
2. Description of the Related Art
An organic light-emitting diode (OLED) display screen has been widely used in display device due to its following advantages: thin and light structure, wide visual angle, active light-emission, continue adjustment of emitting light color, low cost, quick response, low power consumption, low drive voltage, wide range of work temperature, simple manufacturing process, high emission efficiency, and the capability of becoming flexible and the like.
According to the driving modes, the OLED may be divided into Passive Matrix (PM) OLED and Active Matrix (AM) OLED. In the PMOLED, the anodes and the cathodes are arranged in matrix manner, and the pixels in the array may be lighten in scanning manner, wherein, each of the pixels woks in the short-duration pulse mode and may emit light with high luminance for a moment. The PMOLED has a simple structure and may lower the manufacturing cost efficiently, but is not suitable for a display panel with large scale and high resolution due to the relatively high drive voltage. In the AMOLED, each of the pixels is controlled by using an independent TFT (Thin Film Transistor, TFT) and may emit light continuously and independently under drive of TFT. The AMOLED has lower drive voltage and longer life time and may be applied to a display panel with large scale, but has relatively complicated manufacturing process and relatively high cost.
According to the light-emission types, the AMOLED may be divided into top-emission type (the light is emitted out from the upper substrate) AMOLED and bottom-emission type (the light is emitted out from the lower substrate) AMOLED. FIG. 1 is a schematic view of sectional structure of a pixel unit at the position of TFT of bottom-emission type AMOLED array substrate in prior art. The pixel unit comprises: a substrate 1, a gate 22 located on the substrate 1, a gate insulation layer 4 covering the gate 22, an active layer 5 located on the gate insulation layer 4 and opposite to the position of the gate 22, a source 6 and a drain 7 oppositely provided on the active layer 5, a first insulation layer 8 located on the source 6 and the drain 7, and a transparent electrode 23 connected to the drain 7 through a via 9 penetrating the first insulation layer 8, wherein, a part area of the gate 22 is aligned with the position of the drain 7, thereby a storage capacitor 100 is formed therebetween.
The array substrate of the bottom-emission type AMOLED is provided with TFTs and metal wires, which block a part of light and become an important factor impacting on an aperture ratio of pixel (the aperture ratio means the ratio of an area of the pixel capable of emitting light to an area of the pixel). More particularly, in order to solve the problem of nonuniform display image quality due to the differences among pixels, a pixel structure with compensation circuitry is widely proposed, wherein, the pixel unit comprises two or more TFTs. With respect to the bottom-emission type structure, the pixel area occupied by the TFTs and the metal wires is larger; the aperture ratio of pixel is smaller, therefore, the luminance of emitted light should be increased accordingly, the light-emission device will certainly have increased power consumption and shorten life time. As a result of this, the improvement of the aperture ratio of pixel is becoming a pressing problem to be solved.